What a sad kind of people stumbling over the fact he stayed in a hotel in Malta, while being paid for. Who cares and whose business is it anyway?
We staid in quite some resorts in the carribean while being a missionary, all paid for by friends and relatives, taking leave.
What do you expect...him refusing the offer? That would have another reason for stumbling. It's quiet rude what that brother did, calling him and asking him questions about it. Again...if that's what make you stumble, it says it all about your own life.